topic Re: How to avoid preview is Evaluating in Power BI Desktop in Developer

How to avoid preview is Evaluating in Power BI Desktop

Suraj_Ncircle — Fri, 22 Mar 2024 11:14:51 GMT

Hey everyone,

I'm currently working on developin a custom connector in Power BI desktop and have noticed a particular behavior when the checkbox of a table is clicked in navigator. Upon clicking, a "Preview is Evaluating..." message appears on the right side of the navigator, and it takes approximately 5-10 minutes for a truncated table to load. This loading message can be misleading for users, as they might assume they need to wait for the preview when they could instead click on "Load" to directly load the table into the data pane.

Are there any techniques or settings within the Power BI connector code or Power BI desktop application that could help mitigate this issue?

Re: How to avoid preview is Evaluating in Power BI Desktop

lbendlin — Fri, 22 Mar 2024 20:27:39 GMT

Are there any techniques or settings within the Power BI connector code or Power BI desktop application that could help mitigate this issue?

Yes, but they are not practical. The essence of the technique is "Never ever change the meta data ever again".

Re: How to avoid preview is Evaluating in Power BI Desktop

Suraj_Ncircle — Tue, 26 Mar 2024 13:05:13 GMT

lbendlin
Thank you for your response. Could you please clarify your explanation? I'm having difficulty understanding your point. I'm looking for a way to bypass the Preview of the table in Navigator when loading a table in Power BI Desktop via a custom connector.

Re: How to avoid preview is Evaluating in Power BI Desktop

lbendlin — Tue, 26 Mar 2024 13:06:54 GMT

There is no remedy. Whenever you change the meta data this will happen.

Re: How to avoid preview is Evaluating in Power BI Desktop

Suraj_Ncircle — Wed, 12 Jun 2024 18:08:35 GMT

lbendlin
Thank you for your response. I discovered that the Preview feature is also impacting the performance of the connector. Using the diagnostics tool, I found that the same API is called multiple times. I suspect these multiple calls are due to the Preview and data loading processes. The connector performs over 500 API calls, transforming each call into a table, which significantly affects performance. My question is: if we cannot stop this behavior, is there a way to limit the Preview data?